Steam-boiler.



WITNESSES C. D. MOSHER.

STEAM BOILER.

APPLICATION FILED IAN. 3I| I912.

Patented Aug. 24, 1915.

2 SHEETSSHEET I.

C. D. MOSHER.

STEAM BOILER.

APPLICATION FILED JAN.3I,1912.

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WITNESSES CHARLES D. MOSHER, OF NEW YORK, N. Y., ASSIGNOR, BY MESNEASSIGNMENTS, TO THE BABGOCK & WILCOX' COMPANY, OF BAYONNE, NEW JERSEY, ACORPORATION on NEW JEnsnY.

. STEAM-BOILER.

Specification of Letters Z Patent. Patented Aug. 24, 1915. 7

Application filed January 31, 1912. Serial N 0. 674,626.

To all whom, it may concern:

Be it known that I, CHARLES D. MOISHIQR, a citizen of the United States,residing in the borough of Manhattan of the city of New York, in theState of New York, have invented certain new and useful Improvements inSteam-Boilers, of which the fol lowing is a specification, reference beng bad to the accompanying drawings, which form a part hereof.

The object of this invention is to provide highly eflicient means forheating the air which is to be supplied to the fire-box of a steamboiler for the purpose of supporting and promoting, combustion therein,the heat being derived from the products of combustion after theabsorption of heat therefrom by the water in the boiler.

The invention is realized most advanta-- geousl y in connection withwater tube boilers which comprise a steam drum, one or more water-drums,and water tubes which connect the steam drum with the water drum or withthe water tubes and will be explained hereinafter with reference to itsembodiment in a boiler of the general class referred to, although it iscapable of a wider application.

In the accompanying drawings in which the invention is illustratedFigure1 is a view partly in front elevation and partly in transverse section,on opposite sides of a median line, of a water tube boiler to which theinvention is applied. Fig. 2 is a partial view of the same in horizontalsection. Fig. 3 is'a view of the same partly in side elevation andpartly in longitudinal section.

Fig. 4 is a partial view of the same in horizontal section below thewater drum. Fig. 5 is a detail view in perspective illustrating apossible detail of construction.

The boiler shown in the drawings compri'ses a casing a, a steam drum 7)two water drums 0 and water tubes (Z whlch connect the steam drum withthe water drums. The

boiler maybe-heated by gaseous," liquid or "much as possible of theirheat, pass on their way to the stack 2', a grid damper I: beinginterposed in the uptake and provided with the usual openings is for thepurpose of regulating the flow of the heated gases. All of these partsare shown as arranged as usual in boilers of the class referred to, but

"may be arranged in any suitable manner.

In the development of this invention regard has been had to the knowndifficulty of heating considerable volumes of air, whether stationary ormoving, within which there is no internal circulation, it be- .ing wellknown that air and other inert particle of air in contact with the bodyof different temperature. This is true of air in motion either through atube or around it, the sheath or layer of air next the tube alonebecoming cooled or heated as the case may be and acting as an insulatinglayer as to other portions. For this reason the tubular air heatersheretofore employed have a low 'efliciency and require a very large areaof heating surface to produce substantial results. Furthermore the airheaters which are made up of tubes, especially when the tubes are in ahorizontal position, quickly lose a large portion of their originalefficiency through the settlement of soot on the upper sides of thetubes, which effectively insulates about one-third of the availableheating surface of each tube.

By the present invention the objections to the use of tubular airheaters are overcome by the formation, in the uptake h or wherever elsethe hot gases are available after they have given. up heat to thegenerator, of alternating passages h for the hot gases and relativelythin or narrow passages l for the air to be heated, the latter beingadapted to receive at one end the air to be heated and todeliver it atthe other end to suitable channels by which the heated air is con- Iducted to the furnace Furthermore, the

passages are corrugated or waved or sinuous so that the hot gases ofcombustlon, being deflected back and forth in their passage,- 'impingenearly at right vangles upon the .ably made as little: as is consistentwith the supply of v the required volume of air in order that theinsulating effect of the sheath or outer layer of the air may be reducedas much as possible and the'entire volume of air heated to as high adegree as possible.

The alternating passages for hot gases and air may be 'formedconveniently as represented in Fig. 5, in which the sheets Z of metalwhich form the wallsof the passages are secured to end plates Z It iswell understood that uptake and gas passages which are sufficientlylarge to accommodate the waste gases when a boiler is being fired to amaximum degree, are too large when the boiler is being fired at a lowrate of combustion on account of the smaller volumes of gasevolved, andthat in this latter condition the gases tend to short-circuit and failto pass in contact with all of the tube surfaces, with a consequent lossof efficiency. therefore suitably spaced or distributed so as to causeasubstantially equal distribution of the gases over all portions of thetube surface and each of such passagespreferably registers at its upperend with a corresponding aperture or line of apertures 70 in the griddamper la vso that, when the damper is adjusted for different rates ofcombustion the equal distribution of the gases will still be maintained.At their forward ends the air passages communicate with an air header mwhich is formerl -within the casing a of the boiler at the front and isprovided with dampers m by which the-admission'of air may be regulatedand controlled. At their rear ends'the air chambers or conduits Zcommunicate with an air header n which is for the heat of the rear wallof the furnace The gas spaces or passages 71/ are and further heat theair which is guided and distributed by them on the way to the combustionchambers; and they also act as stays to keep the plate to which they aresecured The air header a may also ,the uptake, after they have given upto the water tubes a large proportion of their heat,

impinge upon the walls of the airpassages Z and give up still more oftheir heat to the air which, in passing through these corrugatedheaters, is itself made to impinge upon the heated walls. A constantsupply of fresh air being admitted to the heaters through the frontdampers m and the front header n and a flow thereof being inducedthrough the action ofthe draft, highly heated air is constantly suppliedby the heaters and is deliveredto the ash pit below the grate or to thecombustion chamber above the grate, being further heated and distributedto various points by the webs n.

It will be understood that the details of construction and arrangementmay be varied to suit different boilers and different conditions ofuse,and that the invention is not limited to the particular constructionand to end plates so as to form between them in alternation passagescommunicating with the combustion chamber and the stack and passagesthrough corresponding openings in the end plates communicating with theatmosphere and the combustion chamber, heat radiating webssecured to therear wall of the combustion chamber anddisposed in the passages betweenthe air heater and the combustion chamber, the sheets being spaced todistribute equally the hot gases from the combustion chamber, andadjustable dampers to control the flow of hot gases through the passagestherefor.

This specification signed and witnessed this 30th day of January A. D.,1912.

, 5 CHARLES D. MOSHER. Signed in the presence of- DoRo'rHY DAMES,

. WoR'rmNc'roN CAMPBELL.

